scholarly journals Calcium-Binding Properties of Sarcoplasmic Reticulum As Influenced by ATP, Caffeine, Quinine, and Local Anesthetics

1968 ◽  
Vol 52 (4) ◽  
pp. 622-642 ◽  
Author(s):  
Arselio P. Carvalho
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Local Anesthetics ◽  
Calcium Binding ◽  
Rabbit Skeletal Muscle ◽  
Cellular Membranes ◽  
Binding Properties ◽  
45Ca Fluxes

Calcium retained at binding sites of the sarcoplasmic reticulum membranes isolated from rabbit skeletal muscle requires 10-5 - 10-4 M ATP to exchange with 45Ca added to the medium. The ATP requirement for Ca exchangeability was observed with respect to the "intrinsic" Ca of the reticulum membranes and the fraction of Ca that is "actively" bound in the presence of ATP. Furthermore, a concentration of free Ca in the medium higher than 10-8 M is required for ATP to promote Ca exchangeability. This exchangeability is not influenced by caffeine, quinine, procaine, and tetracaine, and Ca that is either nonexchangeable (in the absence of ATP) or exchangeable (in the presence of ATP) is released by 1–5 mM quinine or tetracaine, but neither caffeine (6 mM) nor procaine (2–5 mM) has this effect. Quinine or tetracaine also releases Ca and Mg bound passively to the reticulum membranes. A possible role of ATP in maintaining the integrity of cellular membranes is discussed, and the effects of caffeine, quinine, and of local anesthetics on the binding of Ca by the isolated reticulum are related to the effects of these agents on 45Ca fluxes and on the twitch output observed in whole muscles.

scholarly journals Calcium-Binding Properties of Sarcoplasmic Reticulum As Influenced by ATP, Caffeine, Quinine, and Local Anesthetics

1968 ◽  
Vol 52 (3) ◽  
pp. 622-642 ◽  
Author(s):  
Arselio P. Carvalho
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Binding Sites ◽  
Local Anesthetics ◽  
Calcium Binding ◽  
Rabbit Skeletal Muscle ◽  
Cellular Membranes ◽  
Binding Properties ◽  
45Ca Fluxes

Calcium retained at binding sites of the sarcoplasmic reticulum membranes isolated from rabbit skeletal muscle requires 10-5 – 10-4 M ATP to exchange with 45Ca added to the medium. The ATP requirement for Ca exchangeability was observed with respect to the "intrinsic" Ca of the reticulum membranes and the fraction of Ca that is "actively" bound in the presence of ATP. Furthermore, a concentration of free Ca in the medium higher than 10-8 M is required for ATP to promote Ca exchangeability. This exchangeability is not influenced by caffeine, quinine, procaine, and tetracaine, and Ca that is either nonexchangeable (in the absence of ATP) or exchangeable (in the presence of ATP) is released by 1–5 mM quinine or tetracaine, but neither caffeine (6 mM) nor procaine (2–5 mM) has this effect. Quinine or tetracaine also releases Ca and Mg bound passively to the reticulum membranes. A possible role of ATP in maintaining the integrity of cellular membranes is discussed, and the effects of caffeine, quinine, and of local anesthetics on the binding of Ca by the isolated reticulum are related to the effects of these agents on 45Ca fluxes and on the twitch output observed in whole muscles.

scholarly journals Properties of the non-specific calcium-binding sites of rabbit skeletal-muscle myosin

1980 ◽  
Vol 185 (1) ◽  
pp. 265-268 ◽  
Author(s):  
J Wikman-Coffelt
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Binding Sites ◽  
Calcium Binding ◽  
Light Chains ◽  
Binding Properties ◽  
Skeletal Muscle Myosin ◽  
Heavy Chains ◽  
Calcium Binding Sites ◽  
Muscle Myosin

The non-specific Ca2+-binding sites of skeletal-muscle myosin are located on the light chains; with the dissociation of light chains there is a corresponding decrease in the number of Ca2+-binding sites on light-chain-deficient myosin. The released light chains have a decreased binding affinity. Myosin heavy chains indirectly influence the Ca2+-binding properties of light chains by increasing the affinity of light chains for bivalent cations; this influence varies with pH. Because of light-chain dissociation at low Ca2+ and/or Mg2+ concentrations, anomalies may exist when analyses of non-specific Ca2+-binding properties of myosin are assessed by dialysis equilibrium.

Calcium binding to the sarcoplasmic reticulum of rabbit skeletal muscle

Biochemistry ◽  
1971 ◽  
Vol 10 (14) ◽  
pp. 2733-2737 ◽  
Author(s):  
Ronald A. Butow ◽  
Jean Chevallier
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Binding ◽  
Rabbit Skeletal Muscle

scholarly journals Utilization of troponin C as a model calcium-binding protein for mapping of the calmodulin-binding sites of caldesmon

1997 ◽  
Vol 321 (3) ◽  
pp. 873-878 ◽  
Author(s):  
Alexei A. POLYAKOV ◽  
Nikolai B. GUSEV
Keyword(s):  
Skeletal Muscle ◽  
Atpase Activity ◽  
Binding Sites ◽  
Calcium Binding ◽  
Binding Protein ◽  
Troponin C ◽  
Rabbit Skeletal Muscle ◽  
Actomyosin Atpase ◽  
Calmodulin Binding ◽  
Central Helix

Troponin C, a structural analogue of calmodulin, was used for mapping the calmodulin-binding sites of caldesmon. The apparent Kd values for the formation of the caldesmonŐcalcium-binding-protein complex as determined by native gel electrophoresis were 0.5, 1.2 and 3.9 ƁM for calmodulin, rabbit skeletal muscle troponin C and bovine cardiac troponin C respectively. Troponin C induced a 4Ő6 nm blue shift of the Trp fluorescence of caldesmon without affecting the amplitude of fluorescence. In the presence of Ca2+, troponin C induced partial displacement of caldesmon from actinŐtropomyosin complexes. Addition of 5,5ƀ-dithiobis(nitrobenzoic) acid to an equimolar complex of caldesmon and troponin C induced disulphide cross-linking between Cys-98 of rabbit skeletal muscle troponin C and the single Cys residue of duck gizzard caldesmon, located in a position analogous to Cys-580 of the chicken gizzard protein. The cross-linked caldesmonŐtroponin C complex was ineffective in inhibiting actomyosin ATPase activity. It is concluded that Cys-580 of caldesmon can be located close to both the central helix of calcium-binding proteins and the C-terminal domain of actin. This may be important for the regulation of actomyosin ATPase activity by caldesmon.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

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